Cathead



Patented Nov. 4, 1941 UNTED STATES PATENT OFFICEy 2 Claims.

' This invention relates generally to hoisting devices and pertains particularly to improvements in catheads.

Catheads as now used on hoists, draw-works, Winches, etc., are keyed solid to the supporting shaft or are bolted to a member which is attached to the shaft. On heavier type equipment these catheads soon have grooves worn therein near the driving shaft or member on which they are mounted and when this groove wears to a certain depth, it becomes a source of danger and it is necessary to remove the cathead so that the same may be sent to a shop to be built up and machined. Oftentimesit is impossible to pull the cathead and key with ordinary tools and it then becomes necessary for the operator to call in someone having special tools for eifecting the removal `of the head from the shaft. In addition to the fact that this procedure is time-consuming and costly, it has been found that built up and machined catheads never wear so well or give as good service as the new catheads.

The present invention has for its primary object to provide an improved cathead wherein the cable carrying or supporting portion is attached to the supporting shaft through the medium of a collar, in such a manner that it may be readily removed when it has become excessively worn f or replacement by a new unit. This replaceable unit of the cathead can be manufactured at reasonable cost and, therefore, when it becomes Worn, it may be discarded and a new unit substituted and the cost involved will not be as great as the cost of having the old style cathead removed, built up and machined.

Another object is to provide in a cathead structure, a novel means for coupling the cable supporting unit or sleeve with the supporting shaft whereby such unit may be applied or removed by a rotary motion with respect to a supporting intermediate part or collar which is keyed to the shaft so that when it becomes necessary to break the sleeve or cable supporting unit loose from the collar, this may be accomplished by wrapping the cable around the unit in the reverse direction t-o that in which it is wrapped when using the unit, securing one end of the cable to a fixed object and then turning the cathead so that when sufficient friction has been built up between the cable and the unit, the unit will free itself from the supporting collar to which it is attached. y

Another object of the invention is to provide in a structure of the above described character, a means whereby the accidental release of the cable supporting unit or sleeve of the cathead Will be prevented, in the .event that the operator should wrap the cable in the reverse direction on the unit.

The invention will be best understood from a consideration of the following detaileddescription taken in connection with the accompanying drawing forming partof this specification, with the understanding, however, that the invention is not to be conned to any strict con;

formity with the showing of the drawing but may be changed or modied so long as such changes -or modifications mark no material departure from the salient features of the invention as expressed in the appended claims.

In the drawing: y

Fig. 1 is a longitudinal sectional view through the cathead structure embodying the present invention.

Fig. 2 is a section on the line 2 2 of Fig. l.

Fig. 3 is a fragmentary view looking into the recess in the end of the cathead in which the locking key engages.

Referring nowkmore particularly to the drawing, the numeral I designates the end of a shaft on which the cathead is mounted, this shaft having a keyway 2 therein.

The cathead constituting the present invention comprises the head proper or sleeve unit 3 about which the cable is wrapped, this unit being here shown as in the form of a cylinder having they end flanges 4.

The numeral 5 designates the cathead sub which is in the form of a collar member which is mounted upon the shaft I and secured thereto I bythe key 6 which engages in the keyway 2 of the shaft and in a corresponding keyway or groove 1 in the sub.

One end of the head unit 3 is formed to receive a portion of the sub or collar 5 as shown, the collar being exteriorly tapered from the outer end through a portion of its length and the corresponding end of the head 3 being similarly tapered so as to form a tight t or join between the two elements.

The cathead unit 3 s coupled with the sub 5 by means of threads, spiral grooves or spiral wings. There are here shown threads 8 and 9 which are formed respectively upon the opposing faces of the sub and cathead 5 and 3, as shown, but it is to be understood that the invention is not to be confined to the use of this specic form of coupling between the parts as it is obvious that spirally arranged Wings or lugs might be employed or other means whereby the cathead may be locked onto the sub by giving to the head rotary motion with respect to the sub, on the longitudinal axis of the head. It will, therefore, be understood that any reference to a spiral coupling between the head and sub will be understood to include or cover the use of threads, grooves or spirally arranged wings.

As a safety feature for preventing the accidental release of the head from the sub in the event that the operator of the machine should wrap the cable about the cathead in the Wrong direction, a means is provided for locking the head and sub together. Such means may be in the form of a key or pin, the particular means here illustrated consisting of a at key IIl which is disposed in a groove II formed longitudinally in the sub 5 adjacent the inner end of the latter and which extends into a recess I2 in the adjacent end of the head. 'Ihis key is secured against displacement by the cap screw I3.

It has previously been stated that the portion of the sub or collar 5 which extends into the end of the cathead or cable carrying unit 3 is slightly tapered. It will also be noted that this tapered portion is of a diameter at its widest part which is less than the overall diameter of the collar so that there is thus formed a shoulder I4 at the inner end of the taper against which the inner end of the cathead unit or sleeve 3 abuts when it is secured in position on the sub.

It is, of course, well understood by those familiar with the art that in the use of catheads, a cable is wound two or three times thereabout and such cable is held by an operator or secured to another part of a hoist mechanism and is alternately tightened and released so as to effect the desired pull upon the object attached to the other end of' the cable. It will, therefore, be understood that in the use of the present device, the cable must be wound in one direction with respect to the direction of turn or hand of the threads or spiral coupling means between the cathead and the collar 5 so that as strain is put on the cathead, the tendency will be for the head to be tightened up on the collar. If, however, the operator should accidently put the cable around the cathead in the reverse direction the locking key between the head and collar will prevent the accidental loosening or unscrewing of the head. It will also be obvious from this that when it is desired to remove the cathead for replacement by a new one, the detachment of the head from the collar may be easily effected by removing the locking key and then winding the cable on the cathead in the reverse direction to that ln which it is wound when in use and by then attaching an end of the cable to a xed object and rotating the cathead, the head will be loosened and unscrewed as soon as sufficient friction is set up between it and the cable.

It will readily be appreciated from the foregoing that with the present form of cathead, replacements may be made easily and quickly and that there will, therefore, be no tendency on the part ofl the operator to delay replacing the head after it has become dangerously worn and thus the likelihood of serious accidents occurring from the use of worn heads will be avoided. It will also be appreciated that the heads may be economically constructed and that the replacement of a worn head with a new one will be a less expensive proposition than that of having the head built up or repaired as is the present practice.

What is claimed is:

1. A cathead, comprising a collar adapted to be keyed to a shaft, said collar being of reduced diameter inwardly of one end and tapering from the reduction toward the other end, a head in the form of an elongated body having flanged endsV and open at one end, the body being formed at said end to receive the tapered end of the collar, helical coupling means between the opposed surfaces of the head and collar whereby the head may be engaged with the collar or disengaged by axial turning, and a locking key splined in the outer surface of the collar outside of the head and engaging and securing the head against turning on the collar, said collar having a shoulder formed at the inner end of the portion of reducing diameter against which the adjacent end of the head abuts.

2. A cathead unit, comprising a collar adapted to receive and be secured on a shaft, said collar being of constant external diameter from one endI through a portion of its length and having an encircling inwardly extending shoulder at the inner end of the portion of constant diameter, the collar being tapered through the remainder of its length from said shoulder to the opposite end and having screw threads formed therearound from the shoulder through part of the extent of the said tapered portion, the said portion of the collar of constant diameter having a longitudinally extending channel in the surface thereof opening at one end through said shoulder, a head comprising an elongated circular body open at one end, the said open end of the circular body being tapered to receive the tapered portionr of the shoulder and threaded for engagement with the threads of the shoulder, the said open end of the body having an inset shoulder adapted for abutment with the shoulder of the collar, the shoulder of the body having a socket therein for register with said channel, and a key tted and secured in said channel and having an end extended into said socket when said shoulders are in abutting relation.

VWLLE'IT M. SCHULTZ. 

